sql server 性能优化和日常管理维护 笔记

1.将sqlserver Profile收集到的trace 比如 duration >5000ms 的trace 文件 导入到sample 表分析或者用查询优化器顾问分析

 2.可以用ＤＭＶ　动态管理视图来查询分析　ｓｑｌｓｅｒｖｅｒ性能，使用情况，比如　查询最近５０条最耗时的ｓｑｌ．

--总耗CPU最多的前个SQL:
SELECT TOP 20
total_worker_time / 1000 AS [总消耗CPU 时间(ms)] ,
execution_count [运行次数] ,
qs.total_worker_time / qs.execution_count / 1000 AS [平均消耗CPU 时间(ms)] ,
last_execution_time AS [最后一次执行时间] ,
max_worker_time / 1000 AS [最大执行时间(ms)] ,
SUBSTRING(qt.text, qs.statement_start_offset / 2 + 1,
( CASE WHEN qs.statement_end_offset = -1
THEN DATALENGTH(qt.text)
ELSE qs.statement_end_offset
END - qs.statement_start_offset ) / 2 + 1) AS [使用CPU的语法] ,
qt.text [完整语法] ,
qt.dbid ,
dbname = DB_NAME(qt.dbid) ,
qt.objectid ,
OBJECT_NAME(qt.objectid, qt.dbid) ObjectName
FROM sys.dm_exec_query_stats qs WITH ( NOLOCK )
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS qt
WHERE execution_count > 1
ORDER BY total_worker_time DESC;

--平均耗CPU最多的前个SQL:
SELECT TOP 20
total_worker_time / 1000 AS [总消耗CPU 时间(ms)] ,
execution_count [运行次数] ,
qs.total_worker_time / qs.execution_count / 1000 AS [平均消耗CPU 时间(ms)] ,
last_execution_time AS [最后一次执行时间] ,
min_worker_time / 1000 AS [最小执行时间(ms)] ,
max_worker_time / 1000 AS [最大执行时间(ms)] ,
SUBSTRING(qt.text, qs.statement_start_offset / 2 + 1,
( CASE WHEN qs.statement_end_offset = -1
THEN DATALENGTH(qt.text)
ELSE qs.statement_end_offset
END - qs.statement_start_offset ) / 2 + 1) AS [使用CPU的语法] ,
qt.text [完整语法] ,
qt.dbid ,
dbname = DB_NAME(qt.dbid) ,
qt.objectid ,
OBJECT_NAME(qt.objectid, qt.dbid) ObjectName
FROM sys.dm_exec_query_stats qs WITH ( NOLOCK )
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS qt
WHERE execution_count > 1
ORDER BY ( qs.total_worker_time / qs.execution_count / 1000 ) DESC;

找出执行时间最长的10条SQL（适用于SQL SERVER 2005及其以上版本）

SELECT TOP 10
( total_elapsed_time / execution_count ) / 1000 N‘平均时间ms‘ ,
total_elapsed_time / 1000 N‘总花费时间ms‘ ,
total_worker_time / 1000 N‘所用的CPU总时间ms‘ ,
total_physical_reads N‘物理读取总次数‘ ,
total_logical_reads / execution_count N‘每次逻辑读次数‘ ,
total_logical_reads N‘逻辑读取总次数‘ ,
total_logical_writes N‘逻辑写入总次数‘ ,
execution_count N‘执行次数‘ ,
creation_time N‘语句编译时间‘ ,
last_execution_time N‘上次执行时间‘ ,
SUBSTRING(st.text, ( qs.statement_start_offset / 2 ) + 1,
( ( CASE statement_end_offset
WHEN -1 THEN DATALENGTH(st.text)
ELSE qs.statement_end_offset
END - qs.statement_start_offset ) / 2 ) + 1) N‘执行语句‘ ,
qp.query_plan
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) st
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp
WHERE SUBSTRING(st.text, ( qs.statement_start_offset / 2 ) + 1,
( ( CASE statement_end_offset
WHEN -1 THEN DATALENGTH(st.text)
ELSE qs.statement_end_offset
END - qs.statement_start_offset ) / 2 ) + 1) NOT LIKE ‘%fetch%‘
ORDER BY total_elapsed_time / execution_count DESC;

sql server 性能优化和日常管理维护 笔记

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